When determining that an own vehicle is likely to depart from a lane, a lane departure prevention apparatus controls the traveling direction of the own vehicle to prevent the own vehicle from departing from the lane. Apparatuses disclosed in Patent Literatures 1 and 2 control an actuator so as to generate torque rotating a steering shaft (hereinafter, referred to as automatic steering torque), in order to change the traveling direction of the own vehicle to prevent the own vehicle from departing from the lane.
In addition, in Patent Literature 1, when torque is applied to the steering shaft by steering operation of the driver (hereinafter, referred to as driver steering torque) while the actuator is generating automatic steering torque, the apparatus cancels the automatic steering torque under certain conditions.
For example, when driver steering torque is applied in a state where automatic steering torque is generated, a cancellation time or a cancellation torque integrated value is set based on the magnitude of the driver steering torque. Then, if the time period during which the driver steering torque is applied exceeds the cancellation time or the cancellation torque integrated value, outputting the automatic steering torque is stopped.
In addition, in Patent Literature 1, the cancellation time or the cancellation torque integrated value are changed depending on whether the direction of the automatic steering torque and the direction of the driver steering torque are the same or opposite to each other.